Cholestatic pruritus

Specialty: Gastrointestinal.

• Itching of hepatobiliary origin
• biliary pruritus
• pruritus due to retention of bile salts

Why it occurs

• Primary biliary cholangitis (PBC) due to destructive autoimmune inflammation of the interlobular bile ducts
• Primary sclerosing cholangitis (PSC) with multifocal scarring strictures of the intra- and extrahepatic bile duct
• Intrahepatic cholestasis of pregnancy due to genetic and hormonal susceptibility in the third trimester
• Extrinsic or intrinsic neoplastic extrahepatic biliary obstruction (cholangiocarcinoma, adenocarcinoma of the head of the pancreas, distal choledocholithiasis)
• Acute hepatitis (viral, toxic or alcoholic) with severe intrahepatic cholestatic component.

Initial workup

Complete liver analysis: total and fractionated bilirubin, alkaline phosphatase (ALP), gamma-glutamyl transferase (GGT), transaminases (AST, ALT), prothrombin time (INR) | Determination of antimitochondrial antibodies (AMA) for PBC and antineutrophil cytoplasmic antibodies (p-ANCA) for PSC | Ultrasound of the upper abdomen (initial evaluation to rule out bile duct dilation) | Magnetic resonance cholangiography (MRCP) or liver biopsy if small bile duct pathology is suspected.

Standard management

• Anion exchange resins — cholestyramine 4 g in sachets, administered 1 to 4 times a day diluted in water; It acts by binding bile acids in the intestinal lumen, preventing their enterohepatic recirculation; should be spaced out from taking other drugs
• Rifampicin — 150-300 mg twice a day, enzyme inducer that decreases the synthesis of pruritogenic metabolites through the pregnane X receptor [PXR] pathway, requiring control of transaminases due to hepatotoxicity
• Opioid antagonists — naltrexone 25-50 mg/day orally, started at low doses to avoid a withdrawal syndrome due to excess endogenous endorphins in cholestasis
• Ursodeoxycholic acid (UDCA 13-15 mg/kg/day to promote hepatocellular bile flow in PBC).